Emc1, a subunit of the endoplasmic reticulum membrane protein complex (EMC), is crucial for the insertion of transmembrane proteins into the ER membrane, ER-mitochondria contact, and lipid exchange [3]. The EMC complex functions as a membrane-protein chaperone, being essential for the proper synthesis, folding, and trafficking of several transmembrane proteins [6]. Genetic models, especially knockout models, are valuable for studying Emc1's functions.

In zebrafish, emc1-/-mutants have severe visual impairments, with extensive retinal abnormalities like photoreceptor layer thinning, smaller outer segments, and disrupted hyaloid vasculature [1]. In mice, Emc1 ablation in photoreceptor cells recapitulates retinitis pigmentosa phenotypes, including attenuated electroretinogram response and progressive degeneration of rod and cone cells, likely due to decreased membrane protein levels [2]. In Drosophila muscle, EMC1 RNAi leads to severe motility defects, muscle morphological aberrations, SR network alterations, cytosolic calcium overload, and mitochondrial dysfunction [3]. In endothelial cells of mice, loss of Emc1 causes defects in retinal vascularization, reduced β-catenin signaling activity through decreased Wnt receptor FZD4 expression [4]. In Drosophila, imbalance of EMC1 (overexpression or knockdown) results in pupal lethality, and glia-specific dosage alterations are lethal, while neuron-specific ones are tolerated, establishing de novo monoallelic EMC1 variants as causative of a neurological disease trait [5].

In conclusion, Emc1 is essential for multiple biological processes, including vision, muscle function, and retinal angiogenesis. Mouse knockout models have revealed its role in retinal-related diseases such as retinitis pigmentosa and familial exudative vitreoretinopathy, and Drosophila models have contributed to understanding its role in neurodevelopmental disorders. These studies provide insights into the biological functions of Emc1 and the mechanisms of related diseases.